fix(test): wait for tenant ready before churn

[skyzh]

Problem

close #9730, as described in the issue

Summary of changes

• Wait for the tenant to be ready before we start to test restarts.

[github-actions]

5418 tests run: 5166 passed, 9 failed, 243 skipped (full report)

---

Failures on Postgres 17

• test_create_churn_during_restart: release-x86-64, release-arm64, debug-x86-64

Failures on Postgres 16

• test_create_churn_during_restart: release-x86-64, release-arm64

Failures on Postgres 15

• test_create_churn_during_restart: release-x86-64, release-arm64

Failures on Postgres 14

• test_create_churn_during_restart: release-x86-64, release-arm64

# Run all failed tests locally:
scripts/pytest -vv -n $(nproc) -k "test_create_churn_during_restart[release-pg14] or test_create_churn_during_restart[release-pg14] or test_create_churn_during_restart[release-pg15] or test_create_churn_during_restart[release-pg15] or test_create_churn_during_restart[release-pg16] or test_create_churn_during_restart[release-pg16] or test_create_churn_during_restart[release-pg17] or test_create_churn_during_restart[release-pg17] or test_create_churn_during_restart[debug-pg17]"

Flaky tests (1)

Postgres 17

• test_change_pageserver: debug-x86-64

Test coverage report is not available

_{The comment gets automatically updated with the latest test results
6896e4e at 2024-11-14T22:58:57.383Z :recycle:}

[skyzh]

ahh... seems like wait_for_tenant_active is not the right function to use